1. Field of the Invention
This invention relates to the use of nanoscale powders as a component of novel composites and devices. By incorporating powders having dimensions less than a characteristic domain size into polymeric and other matrices, nanocomposites with unique properties can be produced.
As it is used herein, the term “agglomerated” describes a powder in which at least some individual particles of the powder adhere to neighboring particles, primarily by electrostatic forces, and “aggregated” describes a powder in which at least some individual particles are chemically bonded to neighboring particles.
2. Relevant Background
A very wide variety of pure phase materials such as polymers are now readily available at low cost. However, low cost pure phase materials are somewhat limited in the achievable ranges of a number of properties, including, for example, electrical conductivity, magnetic permeability, dielectric constant, and thermal conductivity. In order to circumvent these limitations, it has become common to form composites, in which a matrix is blended with a filler material with desirable properties. Examples of these types of composites include the carbon black and ferrite mixed polymers that are used in toners, tires, electrical devices, and magnetic tapes.
The number of suitable filler materials for composites is large, but still limited. In particular, difficulties in fabrication of such composites often arise due to issues of interface stability between the filler and the matrix, and because of the difficulty of orienting and homogenizing filler material in the matrix. Some desirable properties of the matrix (e.g., rheology) may also be lost when certain fillers are added, particularly at the high loads required by many applications. The availability of new filler materials, particularly materials with novel properties, would significantly expand the scope of manufacturable composites of this type.